Induction of a new ribonucleotide reductase after infection of mouse L cells with pseudorabies virus
Induction of a new ribonucleotide reductase after infection of mouse L cells with pseudorabies virus
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伪狂犬病病毒感染小鼠 L 细胞后诱导新型核糖核苷酸还原酶
DOI：
10.1128/jvi.41.3.893-900.1982
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发表时间：
1982
影响因子：
5.4
通讯作者：
L. Thelander
中科院分区：
文献类型：
--
作者：
H. Lankinen;A. Gräslund;L. Thelander
哺乳动物核糖核苷酸还原酶由两个不同的亚基组成，蛋白质M1和M2。M1结合核苷三磷酸变构效应物，而M2含有活性所必需的酪氨酸自由基。核糖核苷酸还原酶的活性增加10倍，在小鼠L细胞提取物感染伪狂犬病病毒后6小时。新的活性不受小牛胸腺核糖核苷酸还原酶M1亚基抗体的影响，而在未感染的细胞中的还原酶活性被完全中和。此外，包装感染的细胞（但不是模拟感染的细胞）显示出细胞核糖核苷酸还原酶亚基M2的酪氨酸自由基的电子顺磁共振光谱。这些数据提供了结论性的证据，即在感染时，疱疹病毒诱导一种新的或修饰的核糖核苷酸还原酶。病毒诱导的酶表现出相同的敏感性，由细胞的还原酶的羟基脲抑制。病毒酶的变构调节与细胞还原酶的调节完全不同。因此，由病毒酶催化的CDP还原显示不需要ATP作为正效应物，并且dTTP或dATP未观察到反馈抑制。病毒还原酶甚至不与以高亲和力结合细胞酶的dATP-琼脂糖柱结合。
The mammalian ribonucleotide reductase consists of two nonidentical subunits, protein M1 and M2. M1 binds nucleoside triphosphate allosteric effectors, whereas M2 contains a tyrosine free radical essential for activity. The activity of ribonucleotide reductase increased 10-fold in extracts of mouse L cells 6 h after infection with pseudorabies virus. The new activity was not influenced by antibodies against subunit M1 of calf thymus ribonucleotide reductase, whereas the reductase activity in uninfected cells was completely neutralized. Furthermore, packed infected cells (but not mock-infected cells) showed an electron paramagnetic resonance spectrum of the tyrosine free radical of subunit M2 of the cellular ribonucleotide reductase. These data given conclusive evidence that on infection, herpesvirus induces a new or modified ribonucleotide reductase. The virus-induced enzyme showed the same sensitivity to inhibition by hydroxyurea as the cellular reductase. The allosteric regulation of the virus enzyme was completely different from the regulation of the cellular reductase. Thus, CDP reduction catalyzed by the virus enzyme showed no requirement for ATP as a positive effector, and no feedback inhibition was observed by dTTP or dATP. The virus reductase did not even bind to a dATP-Sepharose column which bound the cellular enzyme with high affinity.